WO1982001386A1

WO1982001386A1 - Process for keeping exposed surfaces free of ice and snow or thawing them out,piped surface-heating system to carry out the process,and process for the manufacture of such a piped surface-heating system

Info

Publication number: WO1982001386A1
Application number: PCT/AT1980/000032
Authority: WO
Inventors: Herbert Pferschy
Original assignee: Herbert Pferschy
Priority date: 1980-10-15
Filing date: 1980-10-15
Publication date: 1982-04-29
Also published as: EP0062631A1

Abstract

Process for keeping exposed surfaces free of snow and ice or thawing them out by warming the exposed surface with a system of pipes set underneath it, through which cold water at about 6` to 10`C is passed as a warming medium, being preferably taken from underground, circulated through the pipe system and then drained back.

Description

Method for keeping free or defrosting free areas of snow and ice, tube surface heating for carrying out the method and method for producing the tube surface heating

The invention relates to a method for keeping free or defrosting free areas of snow and ice covering by heating the free area by means of a pipe system which is laid beneath it and is heated by a medium which heats the free area, preferably under the action of a circulating device. The invention further relates to a tubular surface heating for carrying out the method and a method for producing the tubular surface heating.

Open spaces are to be understood as traffic areas, sports fields, but also roofs, including gutters and landing bridges. The method according to the invention can also be used as a pipe trace heating method and as a freezer protection for cold stores.

Characteristic of the known prior art

Heating by means of a heating system, be it an electrical system or heating system operated by means of solid fuels, of heated water is extremely energy and cost-intensive. On the other hand, such energy is not always available or must be high

Costs are brought to the place where keeping snow and ice cover free is required.

Object of the invention

The object of the invention is to provide a method with which it is possible to keep free or defrost free areas of snow and ice covering using a heat source which is generally always available. State the nature of the invention

According to the invention, this object is achieved in that cold water is used as the heating medium, which is preferably taken from the groundwater, passed through the pipe system or pumped and then drained off, preferably flushed back into the groundwater.

The invention is based on the knowledge that only a surface temperature is required to keep free areas of snow and ice, but also to defrost existing snow or black ice, which is only slightly above 0 ° C.

Groundwater, but also the deeper water from bodies of water, namely rivers, lakes or in the sea, has a temperature which is generally of the order of at least 6 °, but often up to 10 °. If necessary, the water of a water supply network can also have such temperatures. It is therefore possible, with such cold water, if it is passed through a Rohx system laid under the open space and then drained off again

Keep open space at a temperature slightly above 0 ° C.

For example, water can be taken from the groundwater at a depth that results from the position and the temperature profile of the groundwater as a function of the extraction depth, in order to pump it through the pipe system installed under the open space and then flush it back into the groundwater. You can choose one or more tapping points depending on the size of the free space to be kept free and use the pipe system in a manner known per se in one or more circles, possibly parallel to one another. In accordance with the calculated and necessary flow rate per unit of time to ensure the transport of the necessary heating units, the pipe diameter and pipe spacing as well as the flow rate are measured.

The heat consumption depends on the climatic conditions such as air temperature, wind speed, relative humidity, heat transfer resistance from the open surface to the air or to the snow or ice covering, the thermal conductivity of the pipes in the pipe system and the covering and in particular the thickness of the covering of the pipes by the covering from.

Of course, it makes sense to lay the pipes as close to the surface as possible in order to achieve the greatest possible heat emission from the water used as the heating medium.

The flow rate of the water can optionally be changed automatically depending on the temperature of the coating on the surface and / or inside the coating and also depending on the climatic conditions, so that the heat supply can be limited to the extent necessary.

Snowfall and ice formation from humidity and cold always result in an air temperature from 0 ° C to approx. -6 ° C to -10 ° C. At lower temperatures, snowfall or ice cream formation from air humidity and cold can no longer be expected. Therefore, generally no heat has to be given off from the pipe system at lower temperatures. Rather, it is sufficient if, in a further embodiment of the invention, the flow rate of the water is regulated in such a way that when the external temperature below approx. -6 ° C is just enough to prevent the pipe system from freezing.

The supply of heat and thus the flow rate of the water can thus be restricted to a temperature difference from -6 to -10 ° C. to +1 to + 4 ° C., which advantageously allows the operating costs of the method according to the invention to be reduced.

According to another embodiment of the method according to the invention, the heating can optionally also be set automatically so that, when the air temperature falls below -6 ° to -10 ° C, the open space to be kept free is generally not kept at a temperature above 0 ° C, since at such sluggish temperatures cannot form a slippery surface. It is therefore possible to empty the pipe system when temperatures below -6 ° C are reached, but if the temperature rises again, the pipe system is preheated to slightly above the freezing point of the water before the water is passed through again. This means that when the temperatures above -10 to -6 ° C that are critical for snow and black ice re-emerge, no icing of the groundwater can occur in the pipe system. The pipe system can optionally be heated electrically, for example by using the pipe itself as a heating resistor or embedding it in an electrical heating wire if it is made of a suitable plastic that does not conduct electricity. You can also preheat the water, for example by using an oil, gas or heat pump heater and by means of this preheated water to preheat the pipe system. The heating devices can of course also be put into operation in other cases, which, however, should remain exceptional cases. The efficiency of the method according to the invention can be increased further by improving the heat transfer from the pipe system to the open area by covering the pipe system by means of a coating containing embedded heat-conducting particles.

In order to prevent unnecessary radiation or dissipation of heat in the ground, it is proposed in a further development of the invention to lay a thermal insulation layer under the pipe system or under the supporting structure for the pipe system.

For example, in order to limit the amount of groundwater withdrawn per hour, it can be provided that the cold water is led through a pipe system laid in at least two layers one above the other, preferably firstly the layer closer to the surface and then the lower one (s). Location (s) of the pipe system flows through. The distance between the layers should be at least 5 cm. In the uppermost layer, the groundwater gives off heat to prevent snow and ice formation on the open area. Further heat is given off in the layer or layers underneath, whereby heat is to be prevented from escaping downwards or the heat emission is to be increased upwards.

With a two-layer tube system, e.g. Tubes can be arranged on a reinforced concrete support plate at the top and bottom. In the case of supporting structures for bridges, concrete coverings at airports or similar applications, it is advisable to arrange the second layer of the tube system in the neutral zone of the flexural tension or in the lowest area of the structure.

Of course, a thermal insulation layer can also be arranged under the tube system or under the supporting structure in the case of a multi-layer tube system. The invention further relates to a tubular surface heating, in particular for carrying out the method described above, the tubes through which a preferably liquid heating medium flows are in the form of a snake or register.

In DE-OS 24 42 503 a surface heating is described, with which the object is to be achieved, in particular to avoid the use of additional heating devices, to lay the tubes in such a way that when the outside temperature drops sharply or after a room has been ventilated or outdoors in the case of snowfall or ice formation, the heating has an effect on the surface to be heated when it is switched on, without there being a risk that the floor or the like, ie the embedding material can be damaged by explosive stresses caused by the expansion of the pipes.

This object is achieved according to DE-OS 24 42 503 in that the tubes at a short distance, ie of the order of magnitude

3 cm, are arranged below the surface to be heated and / or consist of a material which, when heated, does not exert any significant explosive stresses on the embedding material surrounding the tubes.

As the pipe material, for example, rubber or the like. provided, i.e. a material that is able to absorb the volume enlargements that occur during heating itself by upsetting, so that they act, if at all, only to a small extent on the embedding material surrounding the tubes.

DE-OS 24 42 503 mentions other measures to solve the task set in it.

The object of the invention is the technically flawless and also cost known from DE-OS 24 42 50 to further develop moderately justifiable tube surface heating, in particular for the purposes of the method according to the invention.

This object is achieved in that the tubes are made of a material or coated with a substance that do not allow a bond between the tube surface and screed or covering material, and that a space is provided for them at the bending or turning points of the tubes.

With this measure it is achieved that the tubes alone can slide on the material of the screed or covering and no friction-resistant connection, but there is a possibility that the thermal expansion, which is now not locally explosive voltage on the enveloping screed or covering acts as a longitudinal expansion at the bending or turning points of the tubes.

For example, the tubes are preferably provided with a film or paint which prevents this friction and makes the tubes slidable accordingly.

An alternative possibility within the scope of the invention is the covering of the tubes with a thin tube made of plastic or a textile material or a mineral fiber fabric.

The free space at the bending or turning points of the

Tubes expediently extend in the horizontal direction on both sides of the turning loop of the tubes.

To create the free space, there are several possibilities in a further embodiment of the invention, for example inserting shaped pieces which can be compressed without any special effort and when together press disintegrate if necessary. Such molded pieces can be, for example, foam molded pieces made of the material known under the trade name Styrofoam or a similar material.

You can insert elastic fittings that the

Thermal expansion of the tubes are compressed and then expand accordingly when the tubes are pulled together.

At the bending or turning points, formwork elements, such as flexible strips, preferably made of plastic, can be inserted, which delimit the desired free space, which can thus be filled with foam at the installation site of the tubular floor heating. It may be possible to use strips treated on the surface in such a way that they can be detached from the resulting foam and used again at another point.

Another possibility is the insertion of air-filled fittings, the shell of which e.g. decomposes after a comparatively short time, so that the elastic pressure between the casing and the heating tube is eliminated.

You can also fill the heating pipes with a liquid when laying them in the embedding material, the temperature of which is of the order of the flow temperature of the pipe surface heating. This will stretch the tubes.

During the solidification of the screed or covering, the hot liquid, which can be water, for example, is replaced by a cold liquid, likewise expediently water, so that the pipe system contracts and thus the desired free space at the turning and bending points is created. If necessary, the heating and cooling process can be repeated several times during the solidification of the embedding material to repeat.

The advantages achievable with the invention can be further increased if pipes are laid in the statically neutral zone of the screed or covering.

This not only results in a desired lifting of the tubes near the surface to be heated by the tube surface heating, but also, in particular, a shift of any remaining bending or tensile stresses into the least stressed area of the screed or covering and finally also a significant amount more uniform heating from the center of the screed or covering so that heat build-ups and the associated bulges with impermissible bending stresses, which can lead to crack formation, are avoided,

For the last-mentioned measure of laying the pipes, the statically neutral zone of the screed or covering is in need of independent protection, since this alone means that inadmissible explosive stresses in the screed or covering are largely independent of the measure of possible sliding movement between the screed or covering and pipes can be reduced.

In a further development of the invention, it is proposed to lay the tubes twice and to feed them with the heating medium in countercurrent. This results in a favorable temperature compensation over the pipe length laid and thus a low stress on the embedding material. This solution is generally usable for tube surface heating.

The double-laid pipes can be combined into a single pipe if the pipe cross-section is divided by an intermediate wall. As a cross-section In the form of such a double tube, an eight cross section is also conceivable in the form of two squares placed one above the other.

Description of the drawing figures

The drawing shows in

1 shows a section from the tube system of the tube heater for rendering the free space to be created at the turning point of a tube;

FIG. 2 shows a data position corresponding to FIG. 1 of a possibility of the flexible embedding of a pipe at a turning point;

3 shows the stress distribution on a pipe laid according to the invention in a screed,

4 is a clip for laying the tubes according to the invention,

5 and 6 two pipe cross sections.

Description of preferred embodiments

In Fig. 1, 1 generally denotes, for example, the screed over a base layer, preferably designed as thermal insulation, in which the heating tubes 2 are laid, of which only one turning point is shown in FIG. 1.

Either you insert a fitting at point 3, which can be compressed without any special effort and, if necessary, disintegrates when compressed, which can be a foam molding, for example, or you insert an elastic fitting that is compressed and expanded as the tube expands then expands again accordingly when the tube 2 is contracted.

But you can also insert an air-filled fitting at point 3, the shell of which e.g. decomposes after a comparatively short time, so that the elastic pressure between the casing and the heating tube is eliminated.

From Fig.2 can be seen at 1 again the screed over a preferably designed as a thermal support layer with a channel 11 for receiving a heating tube, not shown. At 12, this channel is widened and accommodates a possibly multi-part formwork element 13 that delimits the widened part inwards.

Fig. 3 shows at 4 the base layer on which the screed 5 is built. It can be seen that the pipe 6 of the tubular surface heating is moved into the neutral zone, as can be seen from the force areas at 7.

Fig. 4 shows a holder for a tube 8 consisting of a foot 9, which is laid on the support layer 10 and two arms 11, 12 which receive the tube 8 between them in a resilient manner. There are various possibilities for the training of these holders. It is essential that it allows the tube 8 to be lifted from a support directly onto the base layer 10 into the neutral zone.

5 and 6 show two pipe cross-sections for pipes which replace double-laid single pipes by providing a partition in a single pipe, which enables this pipe to be charged with the heating medium in countercurrent. In the cross-section according to FIG. 6, a better heat exchange between the two tube halves is possible due to the larger flat partition wall.

Claims

Patent claims:

1. A method for keeping free or defrosting free areas of snow and ice covering by heating the free area by means of a medium laid beneath it, from a medium that heats the free area, preferably under the action of a circulating device, flow system, characterized in that cold water is used as the heating medium , which is preferably taken from the groundwater, passed through the pipe system or pumped and then discharged, preferably flushed back into the groundwater.

2. The method according to claim 1, characterized in that the cold water is taken from a body of water (river, lake, sea).

3. The method according to claim 1 or 2, characterized in that the flow rate of the water is regulated.

4. The method according to claim 3, characterized in that the flow rate of the water is controlled such that it is just sufficient to prevent the pipe system from freezing when the outside temperature drops below -6 ° C to -10 ° C.

5. The method according to claim 1 or 2, characterized in that when reaching temperatures below -6 ° C to -10 ° C, the pipe system is emptied and when the temperature rises again before passing the water again, the pipe system to something above the freezing point of the water is preheated.

6. The method according to claim 5, characterized in that the preheating of the pipe system by electrical

Heating is made.

7. Method according to one or more of the preceding

Claims 1 to 6, characterized in that the cold water is passed through a pipe system laid in at least two layers lying one above the other, preferably flowing first through the layer closer to the surface and then through the lower layer (s) of the pipe system.

8. Tubular surface heating for carrying out the method according to one or more of claims 1 to 7, characterized in that the pipe system has a cover made of a coating containing heat-conducting particles.

9. tubular surface heating for performing the method according to one or more of claims 1 to 7 and optionally according to claim 8, characterized in that a thermal insulation layer is laid under the pipe system or under the support structure for the pipe system.

10. tubular surface heating according to one or more of claims 1 to 7 and optionally according to claim 8 and / or 9, characterized by a case in

Additional equipment to be used for heating the kait water.

11. Tubular surface heating according to claim 10, characterized by an electrical heating of the pipe system.

12. Tubular surface heating according to claim 10, characterized by the use of a heat pump.

13. Tubular surface heating, in particular for carrying out the method according to one or more of claims 1 to 7, the tubes through which a preferably liquid heating medium flows are laid in a serpentine or register-shaped manner, characterized in that the tubes are made from a material or with a substance are drawn, which do not allow a bond between the tube surface and the laying or embedding material, and that a space is provided for them at the bending or turning points of the tubes.

14. Tube surface heating according to claim 13, characterized in that the tubes are coated with a friction and / or adhesion-reducing paint or film.

15. Tube surface heating according to claim 13 and 14, characterized in that the tubes are covered with a thin tube made of plastic or a textile material or a mineral fiber fabric.

16. Tubular surface heating according to one or more of the preceding claims 13 to 15, characterized in that fittings can be inserted at the bending or turning points of the tubes, which can be compressed without any particular effort, may disintegrate when compressed.

17. surface heating according to claim 15, characterized in that the shaped pieces are foam shaped pieces.

18. Tubular surface heating according to one or more of claims 13 to 15, characterized in that elastic fittings are inserted at the bending or turning points of the tubes, which are compressed during the thermal expansion of the tubes and then expand again when the tubes are contracted.

19. Tubular surface heating according to one or more of claims 13 to 15, characterized in that formwork elements are used at the bending and turning points to delimit a foamable free space at the installation site.

20. Tubular surface heating according to one or more of claims 13 to 15, characterized in that on the Bending or turning points, air-filled fittings are used, the shell of which decomposes after a comparatively short time.

21. A method for producing a tubular surface heating according to one or more of claims 13 to 20, characterized in that the heating pipes are filled with a liquid when laying in the embedding material, the temperature of which is of the order of the flow temperature of the tubular surface heating, and that during the solidification the screed or covering the hot liquid is replaced by a cold liquid.

22. The method according to claim 21, characterized in that the change between hot and cold liquid is repeated several times during the solidification of the embedding material.

23. Tubular surface heating, in particular according to one or more of claims 13 to 20, characterized in that the tubes are laid in the statically neutral zone of the screed or covering.

24. Tubular surface heating, in particular according to one or more of claims 13 to 20, characterized in that the tubes are laid twice and charged with the heating medium in countercurrent.

25. Tubular surface heating according to claim 24, characterized in that the double-laid tubes are combined into a single tube with an intermediate partition separating its cross section into two parts.